Michael

Would heaters plus dehumidifiers be any more efficient than heaters and open windows?

LB

LB,

The de-humidification proposal will use humidity detection to power on and off as it moves through the cycle, thus saving power. In effect it "detects" that the clothes are dry and shuts off the power.

As an aside, the most effective drying room I've encountered was at a remote youth hostel in a mountainous part of the Lake District some 40 years ago. It comprised a large wooden hut behind the hostel building and contained a sizeable old cast-iron coke stove. Painted on the hut floor was a large circle around the stove plus clear warnings that no garments should be left/hung inside the circle otherwise they risked becoming charred or melted. My friends and I thought the warnings were somewhat exaggerated but heeded them nevertheless and were wise to have done so: On returning to the hut several hours later we discovered that the stove was glowing red hot and that the considerable heat inside the hut had thoroughly dried our wet outdoor clothing.

Another aspect which contributed to the effectiveness of the hut was that it had good external ventilators. Though drying rooms don't usually contain red hot coke stoves, it is important for them to have effective natural or mechanical extract ventilation - or humidifiers - in order to remove the humidity generated by the drying process. If not, the humidity inside an enclosed drying room with lots of wet items can approach 100% (saturation point) and thus impede effective drying.

U must also remember that energy efficiency is secondary to ensuring that staff have adequate facilities

Thanks achrn, nicely put.

There seems to be a opinion amongst the posts (reading between the lines) that I am trying to provide a 'cold' drying room. The idea is not simply to put a de-humidifier in to remove moisture (without heating) from the air. The system will 'manage' the relative humidity in the room via a heater, a simple air extraction unit and control unit (monitoring room RH) to tie it all together.

No draconian dictats here

Mick

I never suggested otherwise. My drying room will be well insulated and if designed well enough will benefit from solar gain.



Don't agree with you here. My task stems from an energy saving initiative.

Mick

The extractor fan in our bathroom at home is controlled by a humidity sensor. It runs when humidity is high. It is much better than opening a window because it stops automatically once humidity has dropped. Combine this with a thermostat on your heater you will have covered the two requirements of elevated temperature and removal of damp air.

There are heat exchanges that you can fit to ventilation systems. They use the heat from expelled damp air to warm inlet air from outside. Means you recover some heat so you need less energy for heating.